Ascidia escabanae Monniot 1998

• Main Authors: Sanamyan, Karen, Sanamyan, Nadya
• Format: Other/Unknown Material
• Language: unknown
• Published: 2007
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Ascidiacea; Enterogona; Ascidiidae; Ascidia; Ascidia escabanae; Bering Sea; Pacific
• Online Access: https://zenodo.org/record/5098329; https://doi.org/10.5281/zenodo.5098329

Ascidia escabanae Monniot, 1998 (Figure 3) Ascidia escabanae Monniot, 1998: 544. Ascidia clementea: Sanamyan and Sanamyan, 1998: 212. Not Ritter, 1907: 32. Material examined: RV Keldish, cruise 22, st. 2316, 4294– 4200m, 55°36.8'N, 167°23.04'E – 55°35.0'N, 167°24.4'E, 5–6 August 1990, one specimen. Previous records: NE Pacific, Bering Sea, Escabana Trough of the southern Gorda Ridge (Monniot 1998, Sanamyan and Sanamyan 1998) Description. The specimen is flattened laterally, oval in outline, 3.5 cm high. The colourless, translucent and almost smooth test, with minute sparse conical papillae in places, is thicker on the left side. It contains blood vessels, which are, however, not as conspicuous as originally described for this species and do not differ much from those found in other Ascidia spp. Apertures are on low siphons, the branchial siphon is terminal and the atrial halfway along the dorsal mid-line. The contracted body removed from the test is 2 cm long. Body musculature consists of weak circular siphonal muscles and a network of thin fibers on the right which terminate in a band of parallel transverse fibers along the ventral region. Muscles are not present on the left. A branchial velum is not present. About 25 long, thin tentacles are attached directly to the body wall. The prepharyngeal band of two thin lamellae is in a circle just behind the ring of tentacles. It is not indented dorsally. Papillae were not detected on the body wall between the tentacles and prepharyngeal band. A large, more than 1 mm long, ganglion is just behind a small simple dorsal tubercle. The dorsal lamina has two blades anteriorly which fuse near the middle of the ganglion, and continue posteriorly as a rather high single lamella with minute spaced indentations on the margin (Fig. 3A). The branchial sac is thin and delicate with much reduced tissue. It has more than 60 transverse vessels, and about 50 thread-like internal longitudinal vessels on each side supported on short papillae. Minute intermediate papillae are invariably ...